Tesla P4 ffmpeg bad performance

Hi all,

We are using linux in a dell R740 server with a Tesla P4. We are doing some test with ffmpeg using the GPU and without, we get quite much FPS without using the GPU, what we find weird.

Without GPU

ffmpeg -i Samsung_UHD_Soccer_Barcelona_Atletico_Madrid.ts -threads 0 -map 0:0 -b 500k -c:v libx264 -s 320x240 -y test.h264

frame= 1068 fps= 77 q=-1.0 Lsize= 1282kB time=00:00:21.32 bitrate= 492.5kbits/s speed=1.53x

with GPU

ffmpeg -hwaccel cuvid -c:v hevc_cuvid -i Samsung_UHD_Soccer_Barcelona_Atletico_Madrid.ts -map 0:0 -b:v 500k -c:v h264_nvenc -pixel_format yuv420p -r 25 -vf scale_npp=320:240 -y test1.h264

frame= 415 fps= 66 q=39.0 Lsize= 1044kB time=00:00:16.60 bitrate= 515.4kbits/s dup=0 drop=411 speed=2.62x

The other strange thing is that even if i put to run different processes at the same time, the GPU usage is always the same… around 9%

utilization.gpu [%]
9 %
utilization.gpu [%]
10 %
utilization.gpu [%]
9 %
utilization.gpu [%]
10 %
utilization.gpu [%]

Anybody has experience with ffmpeg to explain this?

Best regards and thanks in advance

Hi, I would assume that you run into the FRL=60fps with the P4. You should remove FRL on the VM level and test again.

Regards

Simon